Nope, in fact you probably need to workout less.
There are two reasons for this:
Firstly, your ability to recover from a training session does not increase at the same rate as your ability to work harder during a training session. In other words you become capable of inflicting more and more physical stress on your body which requires longer and longer periods of time to recover from. As mentioned the other day... no recovery, no benefit.
Secondly, it’s much easier to maintain your fitness than to obtain your fitness. Eventually your progress will suffer from diminishing returns and any further improvements in performance will be much harder to comeby. The good news is maintaining these hard-earned superpowers requires a relatively low volume of training per week.
So there you have it.
Contrary to popular belief you probably need to workout less as your fitness improves!